||This article describes a work or element of fiction in a primarily in-universe style. (May 2013)|
|This article relies on references to primary sources. (May 2013)|
Cover art to Underworld #5.
Art by Sean Scoffield.
|First appearance||Underworld #1 (Feb. 2006)|
|Created by||Frank Tieri
|Alter ego||Jackie Dio|
|Abilities||Regenerative healing factor
Peak human physical attributes
Uses bulletproof sunglasses, weapons with adamantium bullets, and a titanium-lined coat
Fictional character biography
Jackie Dio was a former Silvermane enforcer who was turned over to the cops by his brother Vince. He spent a decade in prison taking out his hatred for super-humans on depowered super-villains imprisoned with him. Once released he found the world had changed a lot in his absence, and that it was difficult to get re-established in the criminal world without powers. He also learned that his brother Vince had become the super-humanly strong Mr. Pain, the crime lord Owl's head enforcer. Against his will, Jackie was covertly given several super-power upgrades himself by the Consultant, an underworld figure who specialised in granting or upgrading powers. Using these new abilities, Jackie confronted and killed Vince, taking on the alias Underworld.
Jackie resurfaced during the Civil War crisis. He had been employed by The Kingpin to infiltrate the rival crime lord Hammerhead's syndicate. Hammerhead first described Underworld as "the new kid on the block" but quickly corrected himself and said "an old kid who just got out of stir and re-entered a new game". Hammerhead was trying to round up other villains to work for him, and villains who disagreed, like Slyde, were killed by Underworld.
Using Underworld, Kingpin lured Hammerhead's forces into an ambush. Underworld escaped this after wounding Hammerhead in the legs, and later caught up with him when he was recovering in a hospital, shooting Hammerhead point blank in the head, seemingly killing him. Hammerhead, however, later resurfaced completely rebuilt as a powerful cyborg by and in the employ of Mr. Negative.
Powers and abilities
As a result of being exposed to a gaseous form of the Super Soldier Serum, Underworld's physical attributes are at the peak of human potential without being superhuman. He is able to lift approximately 700 lb (320 kg) and is stronger, faster, tougher, more agile, and has quicker reflexes & reactions than any Olympic athlete.
Due to an injection of an unknown mutagenic compound by the Consultant (disguised as an underworld doctor), Jackie also possesses a healing factor providing him with vastly accelerated healing abilities. It is sufficiently powerful to fully repair gunshot wounds within a matter of minutes. Unlike the healing factors of some superhumans, such as Deadpool, Jackie's healing factor is even capable of healing old scar tissue, as evidenced by the disappearance of his decade old facial scar.  Jackie may also be resistant to various terrestrial diseases and possibly poisons, though this has not been shown and there is a wide variance among superhumans with healing factors in terms of these resistances.
Underworld wears a pair of unique, extremely durable sunglasses that enable him to see perfectly in the dark and can pinpoint the vulnerabilities of an opponent. The glasses interface with his specially-designed guns and provide a lock onto a target enabling the bullets they fire to change directory in flight much like a guided missile. These bullets are also made of adamantium enabling them to pierce virtually any substance. He wears a long, black coat composed of a titanium weave fabric protecting him from most conventional attacks.
Underworld is a formidable hand to hand combatant, particularly adept at using street fighting techniques. He possesses above-average intelligence and a keen mind for criminal strategy. Underworld is also an expert marksman, and his skills are further enhanced by his glasses' targeting system.
- Civil War: War Crimes
- Amazing Spider-Man #575
- Underworld #5